Divinity 1 took -ages- to get ported to Linux, and the Windows version of Divinity 2 just about launched. I am not sure if getting a port down the road is something they are looking into or not. I guess they are careful now, because the Divinity 1 port has been an absolute disaster (delays piled upon delays). Witcher 3 is a mystery - nobody really knows (for the record, Witcher 1 is NOT on Linux, just 2 is).

Legend of Grimrock was among the first wave of indie Linux games back then. In their case I think they were just not happy enough with the result, or found it too much work. I dunno.

I think Legend of Grimrock was originally one that was ported by the Humble Bundle guys? I could be completely wrong about that.

For the record, it's not like this doesn't happen historically anyhow.

I'm still to this day baffled why SSI released Phantasie 1 and 3 and Questron in a game pack for the Amiga, but never ported Phantasie 2 over to it.

Only the original Bard's Tale was released for the Atari ST, and yet all the way through the Construction Set was released for both the C64 and Amiga.

Would have loved Witcher 1 and 3 ported, I still haven't completed the first one... namely because rebooting or using wine is too time consuming, I'd rather be able to just fire the game up, play for a while, then get back to it later.

I think 'eventually' Divinity: Original Sin 2 should release for Linux. I actually really hope it does an they take their time, because I still need to beat the first one with my Brother!

How about prequels? Knights of the Old Republic II is on Linux but not the first one.